He’s not an aviator.
I didn’t read the entire article, but I assumed that someone with a call sign would be an aviator. Do submariners or surface warfare officers have call signs in the Navy? What for?
Our call signs in the USAF were usually the squadron, the aircraft’s tail number and our crew position. For Example: I was normally Blade-38 Charlie. Blade=37th Aerospace Rescue and Recovery Squadron; 38 - the tail number of our chopper; Charlie=third crew member.